CN110018052B - Rock stretching and pulling shear test device and method - Google Patents
Rock stretching and pulling shear test device and method Download PDFInfo
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- CN110018052B CN110018052B CN201910290252.5A CN201910290252A CN110018052B CN 110018052 B CN110018052 B CN 110018052B CN 201910290252 A CN201910290252 A CN 201910290252A CN 110018052 B CN110018052 B CN 110018052B
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- 239000011435 rock Substances 0.000 title claims abstract description 144
- 238000012360 testing method Methods 0.000 title claims abstract description 34
- 238000000034 method Methods 0.000 title claims abstract description 12
- 239000011148 porous material Substances 0.000 claims abstract description 86
- 238000006073 displacement reaction Methods 0.000 claims abstract description 39
- 238000010008 shearing Methods 0.000 claims abstract description 18
- 230000005540 biological transmission Effects 0.000 claims description 24
- 239000010445 mica Substances 0.000 claims description 9
- 229910052618 mica group Inorganic materials 0.000 claims description 9
- 238000007660 shear property test Methods 0.000 claims description 8
- 238000005520 cutting process Methods 0.000 claims description 6
- 238000002474 experimental method Methods 0.000 claims description 6
- 230000008569 process Effects 0.000 claims description 5
- 235000014121 butter Nutrition 0.000 claims description 3
- 229940099259 vaseline Drugs 0.000 claims description 3
- 230000008859 change Effects 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 claims description 2
- 238000010998 test method Methods 0.000 claims description 2
- 230000008901 benefit Effects 0.000 abstract description 4
- 238000009826 distribution Methods 0.000 description 8
- 238000011160 research Methods 0.000 description 7
- 239000007789 gas Substances 0.000 description 5
- 238000004458 analytical method Methods 0.000 description 4
- 230000006835 compression Effects 0.000 description 4
- 238000007906 compression Methods 0.000 description 4
- 230000006399 behavior Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- 238000009412 basement excavation Methods 0.000 description 2
- 230000001066 destructive effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000001915 proofreading effect Effects 0.000 description 1
- 230000009897 systematic effect Effects 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
- G01N3/10—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces generated by pneumatic or hydraulic pressure
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/24—Investigating strength properties of solid materials by application of mechanical stress by applying steady shearing forces
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A10/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE at coastal zones; at river basins
- Y02A10/23—Dune restoration or creation; Cliff stabilisation
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Abstract
The rock stretching and shearing test device comprises a sample fixing device, a tensile stress applying device and a shearing stress applying device, wherein two pore canals are symmetrically arranged in a rock sample, a kerf parallel to the axis of the pore canals is reserved at the outer end parts of the two pore canals, a pressure air bag is sleeved in each pore canal, and the upper end of the rock sample is connected with a vertical displacement dial for measuring normal displacement quantity of the rock sample; the lateral surface of the rock sample is connected with a horizontal displacement dial plate for measuring the lateral displacement of the rock sample. The rock stretching and pulling shear test device and method have the advantages of simple and feasible structure, reliable performance and accurate test result.
Description
Technical Field
The invention relates to the technical field of rock stretching and tensile shearing damage tests, in particular to a rock stretching and tensile shearing test device and method.
Background
Rock tensile and shear failure are common failure modes in rock mass engineering. For example: deep cavity excavation enables side walls to be normally stressed and unloaded, tangential ground stress is concentrated, and stretching or stretch-shear damage can occur when unloading is very strong. As another example, the unloading of the excavation of a rock slope may cause the upper slope to create a tensile stress zone where the rock mass is typically under a composite tensile and shear stress that is both tensile and shear. And as shown by landslide and earthquake landslide under the action of a large amount of dead weights, the rear edge of the slope body is often damaged mainly by stretching. Therefore, the research of the tensile and shear force characteristics of the rock has important significance for the engineering construction of the rock mass and the evaluation and control of the stability.
Currently, an important means for acquiring rock shear strength parameters is widely applied to geotechnical engineering in rock compression shear tests (including indoor and in-situ tests). However, due to technical difficulties, the tensile shear test of the rock is less developed, the research on tensile shear characteristics is much less than that of compression shear characteristics, the molar coulomb strength criterion fitting straight line obtained by the compression shear test is generally extended to a normal stress axis negative half shaft to serve as the strength criterion of the rock under tensile shear stress, and the treatment is lack of test data support. The existing test method for the tensile shear strength of the rock medium has few researches, and most of the existing research results have complicated test processes, are difficult to operate, have low precision and need to be improved. Many rocks are very inconvenient in the direct control of the tension and the manner in which the tension is applied, and thus improvements in the manner in which the tension is applied to the rock sample are needed.
At present, research on rock compression shear behaviors takes overwhelming advantage in number and depth, while research on tensile shear strength is few, but is increasingly paid attention to. The deformation destructive behavior under the tensile and shear stress of the rock is researched by adopting a direct tensile and shear experiment generally, but the deformation destructive behavior has more limitations, such as inconvenience in direct control of tensile force, difficulty in realizing a complex stress environment and the like. Since experimental data on pull shears is very sparse, theoretical models and experimental data lack systematic proofreading. Most of the existing research results have complicated test processes, are not easy to operate, have low precision and need to be improved.
Disclosure of Invention
The invention provides a rock stretching and pulling shear test device and a rock stretching and pulling shear test method, which have the advantages of simple and feasible structure, reliable performance and accurate test result.
The technical scheme adopted by the invention is as follows:
a rock stretching and shearing test device is characterized in that two pore canals are symmetrically arranged in a rock sample, a kerf parallel to the axis of the pore is reserved at the outer end parts of the two pore canals, a pressure air bag is sleeved in each pore canal,
the test device also comprises a sample fixing device, a tensile stress applying device and a shearing stress applying device.
The sample fixing device is used for fixing a rock sample;
the upper end of the rock sample is connected with a vertical displacement dial plate for measuring normal displacement quantity of the rock sample;
the lateral surface of the rock sample is connected with a horizontal displacement dial plate for measuring the lateral displacement of the rock sample.
The tensile stress applying device comprises a pressure air bag, an inflatable joint, a gas pipeline, a pressurizing pump and a gas source; the air source is connected with the booster pump, the booster pump is connected with the inflation joint through the air transmission pipeline, the inflation joint inflates the pressure air bag, so that the inner wall of the pore canal forms uniform internal pressure, and the rock bridges among the pore canals form upward uniform tension;
the shear stress applying device comprises a cushion block, a sensor, a jack, an L-shaped force transmission piece, a pressurizing pipeline and a pressure pump; an L-shaped force transmission piece is placed on the upper portion of the rock sample, a jack is in contact with the L-shaped force transmission piece, the jack is connected with a sensor, and a pressure gauge is arranged on the pressure pump.
The sample fixing device comprises a left baffle, a right baffle, a triangular baffle, a fixing screw and a screw cap; the left baffle and the right baffle are used for placing the left end and the right end of a rock sample, the left baffle and the right baffle are connected through the fixing screw, the triangular baffle is placed at the left baffle, and the triangular baffle is abutted against the left vertical plate.
A mica gasket is arranged in the middle of the pore canal, butter or vaseline is smeared on the mica gasket,
the vertical displacement dial plate is connected with the top plate, the horizontal displacement dial plate is connected with the left vertical plate, the left vertical plate and the right vertical plate are installed on the bottom plate and form a closed space with the top plate, and the rock sample is placed on the bottom plate.
The pressure air bag is a rubber air bag, and one end of the pressure air bag is provided with an upper symmetrical air inflation connector and a lower symmetrical air inflation connector.
The shear notch of the L-shaped force transmission piece is protruding at the tip, and when shear load is applied, the central axes of the jack and the sensor are positioned on the same horizontal line with the shear notch of the kerf and the L-shaped force transmission piece.
A rock pull shear test method comprising the steps of:
the first step: manufacturing a rock sample with the length multiplied by the width of 2.3d×1.2d, symmetrically arranging two pore canals in the rock sample, wherein the diameter of each pore canal is d, the distance between the two pore canals and a rock bridge is 0.1d, a kerf parallel to the axis of each pore canal is reserved at the outer end parts of the two pore canals, the kerf length is 0.1d, a pressure air bag is sleeved in each pore canal, an upper symmetrical inflation joint and a lower symmetrical inflation joint are arranged at one end of each pressure air bag, and a mica gasket is arranged in the middle of each pore canal;
and a second step of: the left vertical plate and the right vertical plate are arranged on the bottom plate, and then the top plate is arranged to form a closed space;
and a third step of: placing the improved rock sample on a bottom plate, placing a left baffle plate and a right baffle plate on two sides of the rock sample, connecting the left baffle plate and the right baffle plate through a fixed screw, placing a triangular baffle plate at the left baffle plate and abutting against a left vertical upright plate to prevent the rock sample from sliding, and fixing the rock sample;
fourth step: opening an air source, and inflating an inflation joint by an air transmission pipeline connected with a pressurizing pump to ensure that the inner wall of a pore canal forms uniform internal pressure, and rock bridges between the pore canals form upward uniform tensile force to apply normal load;
fifth step: placing an L-shaped force transmission piece on the upper part of a rock sample, extending a jack, wherein the central axes of the jack and a sensor are positioned on the same horizontal line with a shear joint of the rock sample and a shear notch of the L-shaped force transmission piece, so that transverse load is applied;
sixth step: and observing the change values of the vertical displacement dial plate, the horizontal displacement dial plate and the pressure gauge, stopping the experiment after the rock sample reaches the standard required shearing displacement, and recording and storing data in the experiment process.
The invention relates to a rock stretching and pulling shear test device and a method, which have the advantages that:
1: the device has simple and feasible structure and reliable performance, and realizes the application of normal load by changing the characteristics of the rock sample and inflating the inflating joint on the air bag in the pore canal of the rock sample through the inflating joint so that the inner wall of the pore canal is uniformly pressed by the inner wall of the pore canal and the rock bridges between the pore canals are approximately uniformly tensioned. The left baffle and the right baffle of the fixing device and the connection of the bolts enable the sample to be convenient to install and detach. The accuracy of the test result obtained by the invention is ensured.
2: the method can be used for testing and analyzing in places where the pulling-shearing damage is likely to be encountered in geotechnical engineering, thereby providing reliable basis for testing and predicting the occurrence of the pulling-shearing damage of the geotechnical medium.
Drawings
The invention is further illustrated by the following examples in conjunction with the accompanying drawings:
fig. 1 is a schematic diagram of the overall structure of the rock tensile-shear test apparatus of the present invention.
FIG. 2 is a schematic left-hand view of a rock sample fixture of the present invention;
FIG. 3 is a schematic top view of a rock sample fixture of the present invention;
fig. 4 is a schematic diagram of a front view of a rock sample fixture of the present invention.
Fig. 5 is a schematic representation of the preparation of a rock sample of the present invention.
FIG. 6 is a symmetrical arrangement of cells of the present invention;
FIG. 7 is a graph of tangential stress distribution of a rock bridge portion;
fig. 8 is a graph of the tangential stress superposition profile of a rock bridge portion.
Detailed Description
Principle analysis:
in the tensile shear test, the application of shear load is relatively easy, and the key is how to realize the application of tensile stress.
1: according to the mechanical knowledge, after the uniform pressure is realized in the circular pore canal, the radial tension is generated around the pore wall, so that the method can be considered to be applied to the application of the tensile stress under the rock tensile shear test, and the special design of the rock sample property is required.
2: according to the elastic mechanics theory, for an individual pore canal, the radial stress and tangential stress formulas of the pore canal which bear uniformly distributed internal pressure are as follows:
wherein the radial stress sigma ρ Is compressive stress, tangential stressIs tensile stress, R is the inner radius of the pore canal, q is the inner load of the pore canal, and R is the pore canalThe outer radius, ρ, is the distance of a point from the center of the tunnel.
Based on this, as shown in fig. 6, when two tunnels are symmetrically arranged in a rock sample, the diameter is d, and the bridge length is 0.1 d. Taking the pore diameter d of 50mm and the distance between two pores of 5mm, namely the pore diameter of 0.1 times, calculating the tensile stress distribution of the rock bridge part between the pores according to the formula (2) and the stress distribution value after superposition as shown in the following table 1:
TABLE 1 values of distribution of tensile stress and distribution of superimposed stress in the inter-tunnel rock bridge portion
In the table ρ Left side ρ is the distance of a certain point from the center of the left channel Right side Sigma is the distance from a certain point to the center of the right duct Left side Sigma is the tensile stress at a point from the center of the left duct Right side Is a tensile stress at a point from the center of the right duct, wherein sigma Total (S) And (5) adding a value for the tensile stress of the inter-tunnel rock bridge part.
The tensile stress distribution diagram of the rock bridge part between two pore canals is shown in fig. 7:
because the pore canal and the load are symmetrically distributed, tangential stress of the rock bridge part can be directly overlapped, as shown in fig. 8, it can be seen that under the action of symmetrical load on two sides, the rock bridge part is approximately uniformly distributed with tensile stress, as shown in fig. 8:
as shown in the above Table 1, the minimum value of the superposition value of the tensile stress of the rock bridge between the pore canals is 19.05q, the maximum value of the superposition value is 19.28q, the average value of the superposition value is 19.13q, the difference value of the superposition value is 0.077q, the tensile stress of the rock bridge between the two pore canals can meet the requirement of uniform stress, and meanwhile, according to the san-Vinan principle, the cutting slits in the rock mass at the two sides can not influence the stress distribution of the rock bridge in the middle tensile part. From the above analysis, when the pressure uniform load in the pore canal is q, the rock bridge portion between the two pores will form a normal tensile stress approximately uniformly distributed, the magnitude of the normal tensile stress is 19.13q, and when a tensile shear test is performed, the normal tensile force needs to be applied, so that the pressure of the pore canal can be calculated according to the following formula 3, i.e. the pressure value of the air pressure to be charged in the pore canal should be increased.
Wherein q is the internal pressure load of the pore canal, and sigma is the tensile stress of the rock bridge part.
Based on the analysis, a sample with symmetrical pore channels with the length multiplied by the width of 2.3d multiplied by 1.2d shown in figure 5 can be designed, and uniform load is applied in the pore channels, so that rock bridges among the pore channels can be uniformly pulled.
As shown in fig. 1 to 4, a rock stretching and shearing test apparatus includes:
improvement of rock sample properties: two pore canals are symmetrically arranged in the rock sample 26, a cutting seam 28 parallel to the axis of the pore is reserved at the outer end parts of the two pore canals, and a pressure air bag 27 is sleeved in each pore canal.
Based on the stress calculation analysis of table 1, to enable the rock bridge part between two pore canals to form approximately uniformly distributed normal tensile stress, the pore canal diameter of which the distance between the two pore canals is 0.1 times needs to be controlled, and the length of the notch at the outer end of the pore canal is 0.1 times as long as the pore canal diameter.
The test device also comprises a sample fixing device, a tensile stress applying device and a shearing stress applying device:
the sample fixing means is for fixing a rock sample 26;
the upper end of the rock sample 26 is connected with a vertical displacement dial 5 for measuring the normal displacement vector of the rock sample 26; the vertical displacement dial 5 is fixed with the top plate 2 through a dial upright 14.
The lateral surface of the rock sample 26 is connected with a horizontal displacement dial 6 for measuring the lateral displacement of the rock sample 26; the horizontal displacement dial 6 is fixed with the left vertical plate through a horizontal cross rod.
The tensile stress applying device comprises a pressure air bag 27, an inflation connector 18, a gas transmission pipeline 20, a pressurizing pump 21 and a gas source 23; the air source 23 is connected with the pressurizing pump 21 through the air pipe 22, the pressurizing pump 21 is connected with the inflating joint 18 through the air pipe 20, the inflating joint 18 inflates the pressure air bag 27, so that uniform internal pressure is formed on the inner wall of the pore canal, and upward uniform pulling force is formed on the rock bridges between the pore canals, so that the application of tensile stress is completed. The gas source 23 is nitrogen.
The shear stress applying device comprises a cushion block 7, a sensor 8, a jack 9, an L-shaped force transmission piece 10, a pressurizing pipeline 11 and a pressure pump 12; an L-shaped force transmission piece 10 is placed on the upper portion of the rock sample 26, a jack 9 is in contact with the L-shaped force transmission piece 10, the jack 9 is connected with the sensor 8, and the pressure pump 12 is provided with a pressure gauge 13 to record the applied shear stress. The application of shear stress is accomplished by these components. The sensor 8 is an oil pressure sensor, which converts a pressure signal into a resistance signal by a piezoresistive effect, and is used for measuring and controlling the magnitude of a shearing force in this experiment.
The sample fixing device comprises a left baffle 25, a right baffle 24, a triangular baffle 16, a fixing screw 17 and a screw cap 15; the left baffle 25 and the right baffle 24 are used for placing the left end and the right end of a rock sample 26, the left baffle and the right baffle are connected through the fixed screw 17, the triangular baffle 16 is placed at the left baffle 25, and the triangular baffle 16 is abutted against the left vertical upright plate 3. Preventing the rock sample from sliding, thereby fixing the rock sample.
The mica gasket 19 is placed in the middle of the pore canal, butter or vaseline is smeared on the mica gasket 19, the friction effect is effectively reduced, the shearing load is ensured to act on the rock bridge between the two pore canals all the time, and the experimental result is more real.
The vertical displacement dial plate 5 is connected with the top plate 2, the horizontal displacement dial plate 6 is connected with the left vertical plate 3, the left vertical plate 3 and the right vertical plate 4 are arranged on the bottom plate 1, a closed space is formed between the vertical displacement dial plate and the top plate 2, and a rock sample 26 is placed on the bottom plate 1.
The pressure air bag 27 is a rubber air bag, and one end of the pressure air bag is provided with an upper symmetrical air charging connector 18 and a lower symmetrical air charging connector 18.
The shear notch of the L-shaped force transmission piece 10 is in a protruding tip shape, and when shear load is applied, the central axes of the jack 9 and the sensor 8 are positioned on the same horizontal line with the shear notch of the kerf 28 and the L-shaped force transmission piece 10.
Examples:
step one: rock sample installation:
as shown in fig. 1, the rock sample 26 is a rock sample with the length x width of 115mm x 60mm, two pore channels are symmetrically arranged, the diameter of each pore channel is 50mm, the distance between the two pore channels is 5mm, a cutting seam 28 parallel to the axis of each pore is reserved at the outer end parts of the two pore channels, the length of each cutting seam 28 is 5mm, a pressure air bag 27 is arranged in each pore channel, a mica gasket 19 is arranged in the middle of each pore channel, and the rock sample 26 is an object for testing and analyzing the invention.
The sample fixing means is for fixing the rock sample 26;
the tensile stress applying means is for applying a tensile stress to the rock sample 26;
the shear stress applying means is for applying a shear stress to the rock sample 26;
step two: application of tensile stress:
according to the tensile stress value set by the test, the formula (3) is adoptedCalculating the air pressure value required to be applied in the pore canal; and then the air source 23 is opened, the air-charging joint 18 is inflated through the air-conveying pipeline 20, so that uniform internal pressure is formed on the inner wall of the pore canal, and upward uniform tensile force is formed on the rock bridges between the pore canals until the set tensile stress value is reached.
The process can apply set normal tensile stress to the rock bridge part, so as to prepare for the subsequent tensile shear test; the tensile strength of the rock bridge can be measured by directly increasing the internal air pressure values of the pore canals at two sides until the rock bridge breaks.
Step three: application of shear stress:
then, an L-shaped force transmission piece 10 is placed on the upper part of the rock sample 26, the jack 9 is extended, and the central axes of the jack 9 and the sensor 8 are positioned on the same horizontal line with the shear joint of the rock sample and the shear notch of the L-shaped force transmission piece 10, so that transverse load is applied;
the vertical displacement dial 5 records the vertical displacement of the rock sample 26, and the horizontal displacement dial 6 records the horizontal displacement of the rock sample 26;
the pressure air bag 27 is inflated by the air source 23, so that uniform internal pressure is formed on the inner wall of the orifice, and upward uniform tension is formed between the orifices to realize the application of tensile stress; the application of the shear stress is accomplished by means of an L-shaped force-transmitting member 10, wherein a pressure gauge 13 records the magnitude of the applied shear stress.
According to the invention, mechanical knowledge is mainly combined, the pressure air bags 27 in the pore canals of the rock sample are inflated through the air pressure device, air pressure is applied, so that the inner walls of the two pore canals are subjected to uniform internal pressure, tangential stress of the rock bridge parts can be directly overlapped due to symmetrical distribution of pore canals and loads, the rock bridge parts are subjected to approximate uniform tensile force under the symmetrical loads on both sides, so that the application of tensile stress to the rock sample is completed, the rock sample is not separated under the tensile force by the sample fixing device, then the test under the combined state of the tensile stress and the shear stress of the rock sample is performed by the tensile stress applying device and the shear stress applying device, the displacement under the tensile shear state of the rock sample is recorded by the vertical displacement dial 5 and the horizontal displacement dial 6, and the magnitude of the applied shear force is measured by the pressure gauge 13.
Claims (6)
1. A rock tensile shear test method is characterized in that: the rock tensile and tensile shearing test device is adopted, and comprises a sample fixing device, a tensile stress applying device and a shearing stress applying device;
the sample fixing device is used for fixing a rock sample (26);
the upper end of the rock sample (26) is connected with a vertical displacement dial (5) for measuring the normal displacement quantity of the rock sample (26);
the lateral surface of the rock sample (26) is connected with a horizontal displacement dial plate (6) for measuring the lateral displacement of the rock sample (26);
the tensile stress applying device comprises a pressure air bag (27), an inflation connector (18), an air conveying pipeline (20), a pressurizing pump (21) and an air source (23); the air source (23) is connected with the pressurizing pump (21), the pressurizing pump (21) is connected with the inflating joint (18) through the air pipeline (20), the inflating joint (18) is used for inflating the pressure air bag (27) to enable the inner wall of the pore canal to form uniform internal pressure, and rock bridges among the pore canals form uniform pulling force;
the shear stress applying device comprises a cushion block (7), a sensor (8), a jack (9), an L-shaped force transmission piece (10), a pressurizing pipeline (11) and a pressure pump (12); an L-shaped force transmission piece (10) is arranged on the upper part of the rock sample (26), a jack (9) is in contact with the L-shaped force transmission piece (10), the jack (9) is connected with a sensor (8), and a pressure gauge (13) is arranged on the pressure pump (12);
the rock tensile and shearing test method adopting the rock tensile and shearing test device comprises the following steps of:
the first step: manufacturing a rock sample (26) with the length multiplied by the width of 2.3d multiplied by 1.2d, symmetrically arranging two pore canals in the rock sample (26), wherein the diameter of each pore canal is d, the distance between the two pore canals is 0.1d, a kerf (28) parallel to the axis of the pore is reserved at the outer end parts of the two pore canals, the length of the kerf (28) is 0.1d, a pressure air bag (27) is sleeved in each pore canal, an upper symmetrical inflation joint (18) and a lower symmetrical inflation joint (18) are arranged at one end of each pressure air bag (27), and a mica gasket (19) is arranged in the middle of each pore canal;
and a second step of: the left vertical plate and the right vertical plate are arranged on the bottom plate (1), and then the top plate (2) is arranged to form a closed space;
and a third step of: placing the improved rock sample (26) on the bottom plate (1), placing the left baffle plate and the right baffle plate on two sides of the rock sample (26), connecting the left baffle plate and the right baffle plate through the fixed screw (17), placing the triangular baffle plate (16) at the left baffle plate (25) and leaning against the left vertical plate (3) to prevent the rock sample (26) from sliding, thereby fixing the rock sample (26);
fourth step: opening an air source (23), and inflating an inflation joint (18) by an air pipeline (20) connected with a pressurizing pump (21) to form uniform internal pressure on the inner wall of a pore canal, and forming upward uniform tension on a rock bridge between the pore canals to apply normal load;
fifth step: an L-shaped force transmission piece (10) is placed on the upper portion of a rock sample (26), a jack (9) is extended, and the central axes of the jack (9) and a sensor (8) are in the same horizontal line with a cutting joint (28) of the rock sample (26) and a cutting joint of the L-shaped force transmission piece (10), so that transverse load is applied;
sixth step: and observing the change values of the vertical displacement dial plate (5), the horizontal displacement dial plate (6) and the pressure gauge (13), stopping the experiment after the rock sample (26) reaches the standard required shearing displacement, and recording and storing data in the experiment process.
2. The rock pull-shear test method of claim 1, wherein: the sample fixing device comprises a left baffle (25), a right baffle (24), a triangular baffle (16), a fixing screw (17) and a screw cap (15);
the left baffle (25) and the right baffle (24) are used for placing the left end and the right end of a rock sample (26), the left baffle and the right baffle are connected through the fixed screw (17), the triangular baffle (16) is placed at the left baffle (25), and the triangular baffle (16) is abutted against the left vertical plate.
3. The rock pull-shear test method of claim 1, wherein: and a mica gasket (19) is arranged in the middle of the pore canal, and butter or vaseline is smeared on the mica gasket (19).
4. The rock pull-shear test method of claim 1, wherein: the vertical displacement dial plate (5) is connected with the top plate (2), the horizontal displacement dial plate (6) is connected with the left vertical plate (3), the left vertical plate (3) and the right vertical plate (4) are installed on the bottom plate (1), a closed space is formed between the vertical displacement dial plate and the top plate (2), and a rock sample (26) is placed on the bottom plate (1).
5. The rock pull-shear test method of claim 1, wherein: the pressure air bag (27) is a rubber air bag, and one end of the pressure air bag is provided with an upper symmetrical air charging connector (18) and a lower symmetrical air charging connector.
6. The rock pull-shear test method of claim 1, wherein: the shear notch of the L-shaped force transmission piece (10) is in a protruding tip shape, and when transverse load is applied, the central axes of the jack (9) and the sensor (8) are positioned on the same horizontal line with the shear notch of the kerf (28) and the L-shaped force transmission piece (10).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910290252.5A CN110018052B (en) | 2019-04-11 | 2019-04-11 | Rock stretching and pulling shear test device and method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910290252.5A CN110018052B (en) | 2019-04-11 | 2019-04-11 | Rock stretching and pulling shear test device and method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110018052A CN110018052A (en) | 2019-07-16 |
| CN110018052B true CN110018052B (en) | 2024-02-13 |
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| CN201910290252.5A Active CN110018052B (en) | 2019-04-11 | 2019-04-11 | Rock stretching and pulling shear test device and method |
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| CN105043859A (en) * | 2015-08-31 | 2015-11-11 | 潍坊恒联玻璃纸有限公司 | Clamp entering device used for film transversal stretcher |
| CN106124341A (en) * | 2016-06-20 | 2016-11-16 | 三峡大学 | The field direct shear test sample preparation of a kind of Tu Yan interface and assay device |
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| CN104075886A (en) * | 2014-06-24 | 2014-10-01 | 西安理工大学 | Modularized rolling linear guide rail pair combination part static rigidity test method and device |
| CN105043859A (en) * | 2015-08-31 | 2015-11-11 | 潍坊恒联玻璃纸有限公司 | Clamp entering device used for film transversal stretcher |
| CN106124341A (en) * | 2016-06-20 | 2016-11-16 | 三峡大学 | The field direct shear test sample preparation of a kind of Tu Yan interface and assay device |
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